1. Field of the Invention
The present invention relates to a ketoprofen patch appropriate in treating arthritis, and more particularly to a remedy containing ketoprofen, which is percutaneously administrated and has therapeutic effect on arthritis, rheumatism, etc.
2. Description of the Prior Art
Ketoprofen plaster (trade name; KETOTOP, Pacific Pharm. Co., Ltd.) sold at the market as an arthritis remedy which is percutaneously administrated, consists of nonwoven fabric, poly(isobutylene) rubber adhesive as a primer, which is formed on the nonwoven fabric by transfer coating, and mixture of acrylic adhesive, ketoprofen as drug and propylene glycol monolaurate as an enhancer for helping permeation of the drug into skin, which is formed on the primer by transfer coating. Thus manufactured ketoprofen plaster rarely has any difference with the conventional PAS (para-aminosalicylic acid) agent.
U.S. Pat. No. 5,505,956 discloses a ketoprofen patch having 2-5 adhesion layers between a backing as a supporting material and a liner. In the ketoprofen patch, when a non-moisture-permeable backing is used, layers from the backing to a surface layer which is to be contacted with skin, consist of from a layer having a high moisture content to a layer having a low moisture content. On the contrary, when a moisture-permeable backing such as nonwoven fabric is used, layers from the backing to the surface layer which is to be contacted with the skin, consist of from a layer having a low moisture content to a layer having a high moisture content. In order to increase moisture content, the ketoprofen patch uses 0.3-30 wt % of poly(vinyl alcohol), and in each layer, 0.1-40 wt % of ketoprofen is mixed with acrylic adhesive and an enhancer such as propylene monoglycolate.
However, in the ketoprofen patch constructed as mentioned above, since ketoprofen drug exists as a mixture with the acrylic adhesive, even though solubility of ketoprofen is good, diffusion thereof is to be late. In addition, since the release amount of the drug can not be controlled, the amount of drug administered cannot be kept constant over of time. Further, since the ketoprofen which is pulverulent drug, or a non-adhesive type polymer such as the poly(vinyl alcohol) are mixed with the acrylic adhesive, the adhesion strength to the skin is so flimsy that re-attachment of the patch to the skin becomes difficult.
Particularly, because the patch is a medium for transferring drug through the skin, therapeutic effect is proportional to contacting area between the patch and the skin. Therefore, if the area of the patch peeled off from the skin is wide, the drug transferance rate decreases and accordingly, the therapeutic effect remarkably decreases.
Hence, development for a ketoprofen patch having a good adhesion strength for keeping therapeutic effect of drug for a long time, a constant drug release amount per unit time and a good initial drug release characteristic, is highly demanded in this technical field.